1. Field of the Invention
This invention is directed to drive control apparatus for obtaining samples of material, such as coal from a moving stream of crushed coal, for the purpose of analysis of the characteristics of the material.
2. Description of the Prior Art
The need for obtaining samples of various materials, coal being one, from a moving stream has been known, and various arrangements of apparatus have been put forth to accomplish that result. The purpose of coal sampling apparatus is to extract selected samples which are representative of the total flow of the coal as it is delivered from a primary crusher, and to deliver the samples to secondary crusher means associated with means to analyse certain characteristics of the coal.
Coal samplers of the type generally incorporating a swing arm are provided with a bucket which is moved through a falling stream of crushed coal. In this category of prior art are found U.S. Pat. Nos. Jordison 2,977,800 of Apr. 4, 1961; Taylor et al 3,198,017 of Aug. 3, 1965; Jordison 3,541,862 of Nov. 24, 1970; and Clewlow 3,875,803 of Apr. 8, 1975. A portable type coal sampler has been disclosed in the Hines et al U.S. Pat. No. 4,215,579 of Aug. 5, 1980.